I have always managed my books via Calibre and I recently did a firmware update and I can no longer add books this way. I had to do a factory reset tonight as it wasn`t syncing any books that i bought from the kobo store and calibre and also wasn`t holding bookmarks either. It now will sync from kobo desktop but will not show up in my kobo. Calibre sees it on my device, but it`s just not there! what could i be doing wrong, i have been using calibre for years now

something interesting - I just connected adobe digital editions to see if i can load some books onto my kobo and it sees the books i tried to add with calibre on my kobo. calibre is saying its also on my device....and yet i can't see them when i turn on the kobo...
i guess its not a calibre issue but a kobo issue...

It sounds like a book you have copied to the Touch is corrupt in some way and the Touch cannot process

What happens when you sideload a book to a Kobo device , a file is put somewhere on the devices drive. When the device is disconnected, it checks for any new files. If these are files of the type it can display, it processes the files and adds details about them to an internal database. The device uses this database to display the library lists.

If there is a problem with a book during the processing, it does not get added to the database. But, the device will also stop processing other books. So, if you put 10 books on the device, and the first one is corrupt, then none of them will show in the devices library. And as long as that book is on the device, no other sideloaded book will be processed into the devices library.

If you have only put one new book onto the device, you know it is bad. But if you put a lot on together, or still have some from earlier that have not been processed, you have to go through them by trial and error until you find the one causing the problem. The only thing you can do is go through the files on the device when it is connected to the PC and remove those that are not shown in the library on the device. Then put them back on the device one at a time, disconnect the device and see if it is added to the library. If it isn't you have the bad book and can probably add the others safely. But, do those a few at a time in case there are more problems.

If you have only put one new book onto the device, you know it is bad. But if you put a lot on together, or still have some from earlier that have not been processed, you have to go through them by trial and error until you find the one causing the problem. The only thing you can do is go through the files on the device when it is connected to the PC and remove those that are not shown in the library on the device. Then put them back on the device one at a time, disconnect the device and see if it is added to the library. If it isn't you have the bad book and can probably add the others safely. But, do those a few at a time in case there are more problems.

Do we know the order in which the files are processed? I would say alphabetically by file name, which is easy to check from the files that have already been processed. It should then be trivial to identify the next one in line and try again without it.

Do we know the order in which the files are processed? I would say alphabetically by file name, which is easy to check from the files that have already been processed. It should then be trivial to identify the next one in line and try again without it.

If that can help sort (pun intended) things out faster...

I'm a little embarrassed to say I have never done that experiment. So, I just did.

I have five books for testing with the same name except a digit on the end. They are identical except the title in calibre. When sent to the device, they have the same file name except for the number.

My test was to send these books to my Touch with at least a minute between them. The order I sent them was 3, 4, 5, 1, 2. The five books filled the mosaic after the disconnect, but as they have identical text for the first page, I had to look at the library in "Recent reads" order. This showed 5, 4, 3, 2, 1.

That says the books were processed in alphabetical order on file name.

There needs to be another test using files in different directories. But, looking at the database, it appears that it is in path order.

I'm a little embarrassed to say I have never done that experiment. So, I just did.

No need to be even a little embarrassed, David. This is the strength of fora, allowing the pooling of various ideas to come up with better answers!

If your comment on directories proves correct (I'm not in a position to experiment these days and have no reason to believe otherwise), then the processing order will depend on the Calibre save template...